Electrical-energy radiator



April 6, 1929. H. w. NICHOLS 1,709,090

ELECTRICAL ENERGY RADIATOR Filed m 31, 1923 Patented Apr. 16 1929.

UNITED STATES PATENT OFFICE.

HAROLD W. NICHOLS, OF MAPLEVVOOD, NEW JERSEY, ASSIGNOR TO WESTERN ELEC- TRICAL COMPA'NY, INCORPORATED, OF NEW YORK, N. Y., A CORE'ORATION OF NEW YORK.

ELECTRICAL-ENERGY RADIATOR.

Application filed July 31, 1923.

This invention relates to an electrical energy radiator.

When an antenna which is normally adapted for radiation of energy of relatively short wave length, for example, five or six hundred meters is placed on top of a tall building to which it is grounded, difficulties often arise because conducting portions of the building form a part of the effective antenna. In many instances the relation between the effective height of the building and antenna and the wave length intended to be radiated may be such that the radiationcfiiciency becomes very small.

One of the objects of the invention therefore, is to provide an improved electrical energy radiator that, when energized by current of a given frequency, will cause the ourrent to be distributed so that the net area between the current distribution curve and its zero axis may be a maximum.

Another object is to provide means whereby the current in a structure radiating energy at a given wave length may be caused to so distribute itself that energy may be efficiently radiated.

A further object is to so arrange an antenna with respect to the conducting por tions of a building to which the antenna is grounded that the resulting energy radiated fromthe antenna may be a maximum.

A feature of this invention relates to means for compensating for the change of reactance which results when an antenna which is grounded to the conducting frame work of a building is placed in close proximity thereto.

Another feature of this invention relates to a method for increasing the amount of energy radiated from an antenna on top of a tall building by reducing the effective height of the antenna.

- In general this invention may be considered as providing means for causing the conducting portion of a building frame work to radiate energy efficiently. This result is brought about by placing an antenna or a conductingscreen or shield within a few feet of the top of the building and introducing a sosource of energy between the shield or antenna and the conducting portions of the building whereby electrical oscillations may be produced in the building structure through the coupling produced by the capacity be- Serial No. 654,815.

tween the conducting shields or antenna and the building.

The following detail description refers to the drawings in which;

Fig. 1 is a front elevation showing an antenna mounted upon and connected to a building frame work.

Fig. 2 is a curve showing an approximate distribution of current in the structure of F 1?. 1 for a given wave length.

Fig. 3 is a front elevation of the building frame work and antenna of Fig. 1 arranged in accordance with the principles of this invention.

Fig. 4 is a current distribution curve for the antenna structure of Fig. 3 at the same wave length as the curve of Fig. 2.

Fig. 5 is a schematic circuit showing the apparatus connected between the antenna and frame work of Fig. 3.

Referring to Fig. 1, 10 is an antenna mounted upon the conducting building frame work 11. The antenna 10 is supported by towers 12 and 13 and is variable as to height by endless ropes-S and 9 passing over pulley blocks 6 and 7 attached to the towers. The antenna is insulated at its ends from other portions of the structure by strain insulators. Connected between the antenna 10 and frame work 11 by lead-in wire 14 is a source of high frequency electrical energy 15. The building frame work is electrically connected to ground at the point 16.

Fig. 2 illustrates the distribution of current in the structure of Fig. 1 when an alternating electromotive'force ,of a given frequency is applied at 15. The electrical length of the antenna itself is approximately a quarter of a wave length. The source of electrometive force 15 is located at the base. The distribution of current in the antenna and building is approximately as indicated by the curved line 17 of Fig. 2. The exact form of this curve will depend upon the wave length of the energy radiated and upon the structure of the building itself. The form of the current distribution curve, in a partic ular instance, was found to be approximately that shown in Fig. 2. The data from which the curve was plotted was obtained by readings on a wave meter taken at different floors of the building upon which the antenna was located. By this method, the amplitude of current in the building structure was determined. In the particular case in which this curve and the zero line 18 when the areas are taken in an algebraic sense; for example, the distribution shown in Fig. 2 consists of the positive area 20 and 21 and the nega tive area 22. In this case it will be observed that the net area is very small.

In Fig. 3 the antenna of Fig. 1 is shown rearranged to obtain more effective radiation of energy at the same wave length. The effective height of the antenna 10 is reduced. by lowering the antenna to within a few feet of the top of the building frame work by means of the ropes and pulleys 6, 7, 8 and 9. The antenna is supported as in Fig. 1 from towers 12 and 13 fixed to the building frame work 11. A source of electromotive force 15 is shown connected between the antenna and the building structure. The current distribution in the rearranged structure of Fig. 3 is represented by curve 25 of Fig. &. It will be noted in connection with this curve that the positive area 20 has been reduced as compared to corresponding area of curve 17, the

' positive area 21 and negative area 22 remaining substantially the same as in'curve 17, Fig. 2. It is thus evident that the net area "which is proportional to the energy radiated position for maximum radiation must therefore be at some point intermediate to these two extremes. The position for maximum radiation may be-easily determined in any particular instance by trial. In order to obtain the distribution of current shown in the curve, Fig. 4, it is necessary to compensate for the increase in capacity of the radiating structure caused by lowering the antenna 10.

Fig. 5 shows the circuit introduced between V the antenna 10 and the building 11 having a condenser 28, inductance 29, and source of electrornot-ive force-30 connected 1n series.

The variable condenser 28 is connected in series to the antenna to compensate for the increased capacity caused by lowering it. The inductance 29, which is also variable, in combination with the capacity 28, serves to tune the system to the desired Wave length. The values of the capacity 28 and inductance 29 may be predetermined and if desired may be fixed in value.

It is apparent that the radiating structure here described may be adjusted to give maximum radiation of energy at various wave lengths by adjusting antenna 10to the proper elevation and by varying condenser 28 and inductance 29 until the best operation is obtained.

The particular structures and circuits shown and described are merely illustrative of the possible applications of this invention and are-in no way intended to limit its scope. Other arrangements as well as other forms of antennae, and building structures to which the principles of this invention may be applied will readily occur to a person skilled in the art.

What is claimed is:

1. Themethod of increasing the radiating efliciency of an antenna when placed on top and connected to a conducting building structure which comprises adjusting the vertical position of said antenna with respect to said building to obtain a desired distribution of energy-throughout the building and antenna and compensating for change of reactance caused by said adjustment. I

2. In combination, a grounded conducting building framework, a power transmit-ting antenna positioned above said framework and connected to an elevated point thereof, a variable impedance included in said connection, a source of high frequency signal waves connected to said antenna, whereby signals are transmitted, and means adapted to adjust said antenna in a vertical direction, whereby the current distribution throughout the antenna and framework is altered to increase the radiation of energy. a 7

3. In combination, a grounded metallic framework, a horizontal antenna positioned above said framework, a path connecting said antenna to an elevated portion of said framework, said path including in series, an adjustable condenser, an adjustable inductance and a source of signal waves, and means for raising and lowering said antenna while maintaining its horizontal position, whereby a desired currentdistribution may be secured in said antenna and framework.

In witness whereof, I hereunto subscribe my name this 28th day of July, A. D. 1923.

' HAROLD IV. NICHOLS.

CERTIFICATE OF CORRECTION.

Patent No. 1,709, 090. Granted April 16, 1929, to

HAROLD W. NICHOLS.

It is hereby certified that the name of the assignee in the above numbered patent Was erroneously written and printed as "Western Electrical Company, Incorporated", whereas said name should have been written and printed as "Western Electric Company, Incorporated", as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of May, A. D. 1929.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

